:root {
  --bg-color: #F2F2F7;
  --card-bg: #FFFFFF;
  --text-primary: #000000;
  --text-secondary: #8E8E93;
  --accent: #007AFF;
  --accent-hover: #005bb5;
  --accent-disabled: #A1C9F7;
  --border: #E5E5EA;
  --upload-bg: #F9F9FB;
  --upload-hover: rgba(0, 122, 255, 0.05);
  --success-text: #28a745;
  --error-text: #FF3B30;
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.04);
  
  --paper-bg: #ffffff;
  --paper-text: #333333;
  --paper-heading: #111111;
  --paper-link: #0969da;
  --paper-border: #d0d7de;
  --paper-code-bg: #f6f8fa;
  --toc-active-color: #0969da;
  --toc-active-bg: #f0f6fc;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-color: #000000;
    --card-bg: #1C1C1E;
    --text-primary: #FFFFFF;
    --text-secondary: rgba(235, 235, 245, 0.6);
    --border: #38383A;
    --upload-bg: #2C2C2E;
    --paper-bg: #0d1117;
    --paper-text: #c9d1d9;
    --paper-heading: #f0f6fc;
    --paper-link: #58a6ff;
    --paper-border: #30363d;
    --paper-code-bg: #161b22;
    --toc-active-color: #58a6ff;
    --toc-active-bg: #1f2937;
  }
  .paper-content img { filter: brightness(.8) contrast(1.2); }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; overflow-x: hidden; }
body {
  font-family: 'Inter', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  margin: 0; padding: 0;
  -webkit-font-smoothing: antialiased;
  overflow-wrap: break-word;
}

.top-nav {
  position: fixed; top: 0; right: 0;
  padding: 16px 24px;
  z-index: 100;
}
.icon-btn {
  background: transparent; border: none; color: var(--text-secondary); cursor: pointer;
  padding: 8px; border-radius: 50%; transition: all 0.2s; display: flex;
}
.icon-btn:hover { background: var(--upload-bg); color: var(--accent); }

.modal-overlay {
  position: fixed; top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.5); backdrop-filter: blur(4px);
  display: flex; justify-content: center; align-items: center;
  z-index: 2000; padding: 20px;
  opacity: 0; animation: fadeIn 0.3s forwards;
}
@keyframes fadeIn { to { opacity: 1; } }

.modal-card {
  background: var(--card-bg); width: 100%; max-width: 440px;
  border-radius: 20px; box-shadow: 0 20px 40px rgba(0,0,0,0.2);
  display: flex; flex-direction: column; overflow: hidden;
}
.modal-header { padding: 20px 24px 12px; display: flex; justify-content: space-between; align-items: center; }
.modal-header h3 { margin: 0; font-size: 20px; }
.close-btn { background: transparent; border: none; font-size: 24px; color: var(--text-secondary); cursor: pointer; padding: 0; line-height: 1;}
.close-btn:hover { color: var(--text-primary); }

.modal-body { padding: 0 24px 20px; }
.terms-text { font-size: 14px; line-height: 1.6; color: var(--text-secondary); }
.terms-text ul { padding-left: 20px; margin-top: 12px;}
.terms-text li { margin-bottom: 12px; }
.terms-text strong { color: var(--text-primary); }

.modal-desc { font-size: 14px; color: var(--text-secondary); margin: 0 0 16px 0; }
.input-label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 8px; }
.text-input { width: 100%; padding: 12px 16px; border-radius: 12px; border: 1px solid var(--border); background: var(--bg-color); color: var(--text-primary); font-size: 15px; outline: none; transition: border-color 0.2s; }
.text-input:focus { border-color: var(--accent); }
.status-msg { margin-top: 8px; font-size: 13px; text-align: center; min-height: 18px; font-weight: 600; }

.modal-footer { padding: 16px 24px 24px; display: flex; justify-content: flex-end; }
.primary-btn { background-color: var(--accent); color: #FFFFFF; border: none; padding: 16px; border-radius: 14px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.2s; width: 100%; }
.primary-btn:hover { background-color: var(--accent-hover); }
.primary-btn:disabled { background-color: var(--accent-disabled); cursor: not-allowed; }

.view-container { min-height: 100vh; display: flex; justify-content: center; align-items: center; padding: 20px; }
.container { background-color: var(--card-bg); width: 100%; max-width: 420px; border-radius: 24px; padding: 32px 24px; box-shadow: var(--shadow); text-align: center; }

.header-icon { width: 48px; height: 48px; background-color: rgba(0, 122, 255, 0.1); color: var(--accent); border-radius: 14px; display: inline-flex; justify-content: center; align-items: center; margin: 0 auto 16px; }
h2 { margin: 0 0 8px 0; font-size: 22px; font-weight: 600; }
p.subtitle { margin: 0 0 24px 0; color: var(--text-secondary); font-size: 15px; }

.upload-area { background-color: var(--upload-bg); border: 2px dashed var(--border); border-radius: 16px; padding: 32px 20px; cursor: pointer; transition: all 0.2s; margin-bottom: 24px; position: relative; }
.upload-area.dragover, .upload-area:hover { border-color: var(--accent); background-color: var(--upload-hover); }
.upload-area svg { width: 36px; height: 36px; stroke: var(--accent); margin-bottom: 12px; fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;}
.upload-title { font-size: 16px; font-weight: 500; margin-bottom: 4px; }
.upload-desc { font-size: 13px; color: var(--text-secondary); }
#pdfFile { position: absolute; top: 0; left: 0; width: 100%; height: 100%; opacity: 0; cursor: pointer; }
#fileNameDisplay { display: none; margin-top: 12px; font-size: 14px; font-weight: 600; color: var(--accent); background-color: var(--bg-color); padding: 8px 12px; border-radius: 8px; }

#statusContainer { margin-top: 20px; display: flex; flex-direction: column; align-items: center; gap: 12px; }
.loader { display: none; border: 3px solid var(--border); border-top: 3px solid var(--accent); border-radius: 50%; width: 24px; height: 24px; animation: spin 1s linear infinite; }
@keyframes spin { 100% { transform: rotate(360deg); } }
#statusText { font-size: 14px; font-weight: 500; color: var(--text-secondary); }

#paperView { background-color: var(--paper-bg); display: flex; justify-content: center; padding: 40px 24px; align-items: flex-start; }
.paper-layout { display: flex; max-width: 1200px; width: 100%; gap: 40px; position: relative; justify-content: center; }

.paper-content { flex: 1; max-width: 850px; min-width: 0; color: var(--paper-text); line-height: 1.8; font-size: 16px;}
.paper-content h1, .paper-content h2, .paper-content h3 { color: var(--paper-heading); margin-top: 2em; margin-bottom: 0.8em; line-height: 1.4; font-weight: 700; scroll-margin-top: 20px; }
.paper-content h1 { font-size: 2.2em; border-bottom: 1px solid var(--paper-border); padding-bottom: 0.3em; margin-top: 0; }
.paper-content h2 { font-size: 1.7em; border-bottom: 1px solid var(--paper-border); padding-bottom: 0.3em; }
.paper-content h3 { font-size: 1.4em; }
.paper-content a { color: var(--paper-link); text-decoration: none; }
.paper-content a:hover { text-decoration: underline; }
.paper-content p { margin-bottom: 1.2em; text-align: justify; }
.paper-content blockquote { border-left: 4px solid var(--paper-border); padding-left: 1em; opacity: 0.85; margin-left: 0;}
.paper-content pre { background-color: var(--paper-code-bg); padding: 16px; border-radius: 6px; overflow-x: auto; border: 1px solid var(--paper-border); }
.paper-content code { font-size: 0.9em; background-color: var(--paper-code-bg); padding: 0.2em 0.4em; border-radius: 3px; }
.paper-content pre code { background-color: transparent; padding: 0; }
.paper-content table { width: 100%; border-collapse: collapse; margin: 2em 0; display: block; overflow-x: auto; }
.paper-content th, .paper-content td { padding: 10px 14px; border: 1px solid var(--paper-border); text-align: left; }
.paper-content th { background-color: var(--paper-code-bg); font-weight: 600; white-space: nowrap; }
.paper-content img { max-width: 100%; height: auto; display: block; margin: 2em auto; border-radius: 4px; border: 1px solid var(--paper-border); }

.paper-toc { width: 240px; position: sticky; top: 40px; height: calc(100vh - 80px); overflow-y: auto; font-size: 0.9em; border-left: 1px solid var(--paper-border); padding-left: 20px; flex-shrink: 0; }
.toc-title { font-weight: 700; margin-bottom: 1em; text-transform: uppercase; font-size: 0.85em; opacity: 0.6; color: var(--paper-text);}
.paper-toc ul { list-style: none; padding: 0; margin: 0; }
.paper-toc li { margin-bottom: 0.2em; }
.paper-toc a { color: var(--paper-text); opacity: 0.7; display: block; padding: 4px 8px; border-radius: 4px; transition: all 0.2s; text-decoration: none; }
.paper-toc a:hover { opacity: 1; color: var(--paper-link); background-color: var(--paper-code-bg); }
.paper-toc a.active { opacity: 1; color: var(--toc-active-color); background-color: var(--toc-active-bg); font-weight: 500; }
.toc-h2 { margin-left: 0.5em; font-size: 0.95em; }
.toc-h3 { margin-left: 1.5em; font-size: 0.9em; opacity: 0.8; }

.floating-btn { position: fixed; bottom: 24px; right: 24px; width: 56px; height: 56px; background-color: #007AFF; color: white; border-radius: 50%; display: flex; align-items: center; justify-content: center; box-shadow: 0 4px 16px rgba(0,0,0,0.2); z-index: 9999; text-decoration: none; transition: opacity 0.3s, transform 0.2s; }
.floating-btn:active { transform: scale(0.9); }

@media (max-width: 1024px) {
  .paper-toc { display: none; }
  .paper-layout { gap: 0; }
  .paper-content { max-width: 800px; }
}

@media (max-width: 767px) {
  .view-container { padding: 16px; }
  .container { padding: 24px 16px; border-radius: 20px; }
  
  .modal-overlay { padding: 16px; }
  .modal-card { border-radius: 16px; }
  .modal-header { padding: 16px 20px 8px; }
  .modal-body { padding: 0 20px 16px; }
  .modal-footer { padding: 12px 20px 20px; }
  .primary-btn { padding: 14px; font-size: 15px; }
  
  .top-nav { padding: 12px 16px; }
  
  #paperView { padding: 20px 16px; }
  .paper-content { font-size: 15px; }
  
  .paper-content h1 { font-size: 1.7em; margin-top: 1em; }
  .paper-content h2 { font-size: 1.4em; margin-top: 1.5em; }
  .paper-content h3 { font-size: 1.2em; }
  
  .paper-content pre { padding: 12px; font-size: 0.85em; }
  .paper-content th, .paper-content td { padding: 8px 10px; font-size: 0.9em; }
  
  .floating-btn { width: 48px; height: 48px; bottom: 16px; right: 16px; }
  .floating-btn svg { width: 20px; height: 20px; }
}